The present invention refers to an aspiration and irrigation system, especially for performing surgical operations on the eye of a living being to maintain the intraocular pressure, and in particular relates to an aspiration and irrigation system of the type having a pressure unit for supplying a gaseous fluid, an irrigation unit which is in communication with an infusion bottle with dropper for conducting liquid fluid to the eye, and with an aspiration unit for removing tissue and/or fluid from the eye.
U.S. Pat. No. 4,935,005 discloses an ophthalmic fluid flow control system for use with a surgical irrigation and aspiration instrument which is connected with an ultrasonic device and a peristaltic pump. The ultrasonic device is supplied with a liquid irrigation fluid from a container via a fluid conduit including a first valve and a successively arranged control valve in order to attain an ophthalmic irrigation. Subsequently, tissue-containing fluid is removed from the surgical site by the peristaltic pump via an aspiration conduit, which is connected to the ultrasonic device and to a pressure-sensitive transducer, for discharge into a collector. The transducer monitors the suction capacity of the peristaltic pump and thus senses a vacuum rise in the aspiration conduit so that the supply of irrigation fluid can be interrupted when e.g. the selected suction capacity is exceeded through blockage caused by tissue-enriched fluid.
U.S. Pat. No. 4,900,301 discloses an ocular perfusion device in communication with an ophthalmological irrigation and aspiration system in which a pressure-generating pump supplies e.g. an air/gas mixture at a certain output pressure to the infusion instrument via a first conduit of a dropper which is provided with a liquid container adjustable to the level of the eye and via a second conduit which is connected to a multiport valve. A third conduit is linked to the multiport valve for supplying infusion fluid from the dropper to the infusion instrument.
Common to these prior art systems is the drawback that the intraocular pressure is determined by the infusion level of the container which is arranged e.g. on a stand or the like, or on the infusion level of the dropper. In the event, the intraocular pressure should be modified because of e.g. hemorrhaging during a surgical procedure, the change can be accomplished only through a cumbersome and instinctive adjustment of the height of the container or the dropper.